To detect Human IFN-lambda;2 by sandwich ELISA (using 100 ul/well antibody solution) a concentration of 0.25-1.0 ug/ml of this antibody is required. This biotinylated polyclonal antibody, in conjunction with Polyclonal Anti-Human IFN-lambda;2 (TA328346) as a capture antibody, allows the detection of at least 0.2-0.4 ng/well of recombinant Human IFN-lambda;2.